1. Field of the Invention
The present invention relates to a cleaning technique for an inkjet recording head.
2. Description of the Related Art
In a recording head including a nozzle face at which nozzles for discharging ink are provided, paper powder and dust floating in the air (hereinafter, referred to as dust) may adhere on the nozzle face. When such dust adheres, an accuracy of ink droplet impact positions is deteriorated, a condition in which ink droplets do not properly impacted may occur, and an undesired line may be generated in an image. To solve such a problem, a general printer includes a cleaning mechanism for wiping dust off a nozzle face with a wiper made of a flexible material.
Japanese Patent Application Laid-Open No. 3-99857 discusses an example of a printer including a cleaning mechanism. This device performs wiping while pressurizing ink to be supplied to the recording head and overflowing the ink from the nozzle during a cleaning operation. Thus, a wiping effect is improved by preventing dust being pushed into the nozzle by the wiper while wiping. The pressurization is stopped when the wiper moves to an end position, and the ink overflowed on the nozzle face is drawn into the nozzle by a negative pressure in the recording head. Then, a meniscus shape of the ink is formed due to a surface tension of the ink.
According to the device discussed in Japanese Patent Application Laid-Open No. 3-99857, since a large amount of ink is overflowed during wiping, a large amount of ink is gathered by wiping. Further, ink leaks from the nozzle immediately after the wiper passes through. Thus, the gathered ink may flow from both ends of the wiper and mix with the ink overflowed after the wiper is moved.
Accordingly, the dust included in the gathered ink may move back to the nozzle together with the ink. If the large amount of ink on the nozzle face is drawn into the nozzle by a negative pressure when the pressurization is stopped, the dust may be drawn into the nozzle with the ink, and may adhere on the discharge port again. This causes a cleaning failure (see FIG. 10).
Further, the device discussed in Japanese Patent Application Laid-Open No. 3-99857 keeps pressurizing until the wiping ends, there is a problem that a large amount of ink is consumed every time cleaning is executed.